TSC888A gain is low

[john_schimandle]

Posted on January 02, 2013 at 19:50

I'm using the TSC888A current sensing amplifier in BLDC (brushless DC) motor controller current limit circuit. I'm seeing a gain of about 10 from the amplifier instead of the published typical value of 20. The data sheet does not specify a min or max gain but does state an output accuracy of 6%. With a 0.05 ohm series resistor and 1.2A current I am seeing an output voltage of 650mV. According to my calculations I should be seeing 1.2V (1.2*0.05*20).

Vcc and Vp are both connected to same 12V power bus.Has anyone else seen this problem? #tsc888

[john_schimandle]

Posted on January 03, 2013 at 02:22This was pilot error. Gain is correct per the data sheet.

[Anthony BOIMOND]

Posted on January 06, 2013 at 11:13

Hello John,

You were able to find the solution by yourself: thanks for sharing with us!I can add one information: the gain for TSC888 is ''hard-trimmed'' and tested in production line so it's very unlikely to see gain values out of specified values (trimming can hardly change after programming).Best wishes for 2013 and Best regards,Anthony